Method of forming and piercing a thermoplastic strip in one step

摘要

Methods for forming a strip of thermoplastic material by punch clamping are described. One method includes providing a clamping mold with i) a surface having at least one die space and ii) at least one clamp having at least one punch tip located in a punch body; providing a strip of thermoplastic material having a softening temperature and a melting temperature; heating the strip of thermoplastic material to a working temperature higher than the softening temperature and lower than the melting temperature; placing the strip of thermoplastic material in the clamping mold and against the surface and over the at least one die space; forming the strip of thermoplastic material by closing the at least one clamp so as to a) form the strip of thermoplastic material with the at least one clamp and b) pierce the strip of thermoplastic material with the at least one punch tip, in one step; cooling the strip of thermoplastic material to a removal temperature lower than the softening temperature; opening the at least one clamp; and removing the strip of thermoplastic material from the clamping mold. The methods provide advantages in that the time required to form the strip of thermoplastic material is reduced, the need for expensive injection molding equipment is obviated and the configuration of the resultant rings can be quickly modified to permit flexible manufacturing by simply changing the configuration of the clamping mold.